I have already written a first post "Sleep apnea - what is it, how common is it and how does it affect mortality & physical health?" which highlights that sleep apnea is a common, regularly unrecognised disorder, occurring in approaching 1 in 5 adults and that, particularly as it becomes more severe - probably approximately 1 in 10 sufferers (Li et al, 2015) - sleep apnea is linked with a wide range of serious diseases and with significantly increased death rates.  In this second post, I'll look at the relevance of sleep apnea for psychiatric disorders.

How does sleep apnea affect psychological health?  The simple answer is "considerably".  In their paper "Obstructive sleep apnea and psychiatric disorders: a systematic review", Gupta & Simpson looked at 47 research studies published up to the spring of 2014.  They noted evidence of increased sleep apnea in unipolar depression and in PTSD and commented "Studies of treatment of OSA indicate an improvement in both OSA and psychiatric symptoms".   Heck & Zolezzi, in their 2015 paper "Obstructive sleep apnea: management considerations in psychiatric patients" (freely downloadable in full text), point out the double whammy that "Data show that OSA is particularly prevalent in patients with psychiatric disorders. The medical care that patients with these comorbidities require can be challenging, as some of the psychiatric medications used by these patients may exacerbate OSA symptoms."  They write "Overall, the evidence is stronger and is rapidly building for an association of OSA with depression and anxiety" and cite the fairly huge survey of over 4 million patients (Sharafkhaneh et al, 2005) which found an OSA prevalence of 2.9% (they were probably just picking up more severe cases) and commented "Psychiatric comorbid diagnoses in the sleep apnea group included depression (21.8%), anxiety (16.7%), posttraumatic stress disorder (11.9%), psychosis (5.1), and bipolar disorders (3.3%). Compared with patients not diagnosed with sleep apnea, a significantly greater prevalence (P < .0001) was found for mood disorders, anxiety, posttraumatic stress disorder, psychosis, and dementia in patients with sleep apnea."  Direct associations between sleep apnea and psychosis & bipolar disorder currently seem less strong than between apnea and depression & anxiety - however the high prevalence of over-weight in psychosis & bipolar disorder and the adverse effects of related medications may well make apnea more of an issue in these groups.  Interestingly Youssef et al in a careful review found a high prevalence of apnea in ADHD sufferers, with benefits emerging for the ADHD when the apnea was treated.  In the last post on apnea & physical diseases, I mentioned increased problems with cognitive function & dementia.  Possibly somewhat counterintuitively, sleep apnea is also associated with insomnia.  In a 2010 review, Luyster & colleagues - "Comorbid insomnia and obstructive sleep apnea: challenges for clinical practice and research" - commented "A high prevalence (39%-58%) of insomnia symptoms have been reported in patients with OSA, and between 29% and 67% of patients with insomnia have an apnea-hypopnea index of greater than 5. Combination therapy, including both cognitive behavior therapy and OSA treatment, resulted in greater improvements in insomnia than did either cognitive behavior therapy or OSA treatment alone. The use of GABAergic nonbenzodiazepine agents (Z-drugs) has been associated with improvements in sleep and has little to no effect on the apnea-hypopnea index in patients with OSA. Conclusions: Insomnia and OSA frequently cooccur. The optimal strategy for adequately treating comorbid insomnia and OSA remains unclear. Future research examining the impact of insomnia on continuous positive airway pressure therapy is needed. Given the substantial overlap in symptoms between insomnia and OSA, evaluation and treatment of these 2 conditions can be challenging ..."  

So how does sleep apnea affect psychological health?  Current evidence highlights that sleep apnea is often comorbid with depression and with PTSD.  There is also a high incidence of sleep apnea in other psychological disorders as well.  Sleep apnea becomes more common with increasing age (e.g. >50), increasing weight, increasing neck size, with smoking and drinking, and in men (although the male/female difference in prevalence decreases in older adults).  Even if apnea had no effect on psychological symptom severity, we know that sleep apnea is a significant risk factor for a series of serious physical diseases.  People suffering from psychological disorders have worryingly greater death rates than those without significant psychological symptoms - see last year's paper "Mortality in mental disorders and global disease burden implications: A systematic review and meta-analysis" with its comment that "The median years of potential life lost was 10 years".  The increased prevalence of sleep apnea in psychological disorder will contribute to these increased overall death rates.  Mental health professionals need to be more aware of, and engaged with the physical health of those we try to help. There is a huge problem here - see "Clustering of health risk behaviours and the relationship with mental disorders" and "Lifestyle choices and mental health: a representative population survey" - and as this year's exciting paper by Goracci & colleagues shows - "Development, acceptability and efficacy of a standardized healthy lifestyle intervention in recurrent depression" - tackling physical risk factors can have really encouraging benefits for psychological disorders themselves.  In the same way, emerging research strongly suggests that tackling sleep apnea will benefit not only physical health but also psychological health as well. 

In the third & last post in this sequence, I will look at "Sleep apnea - how is it recognised & what can be done about it?"